Biology subjects

Spooren, J.

Publications and source records attributed to Spooren, J..

3 recordsLinked to original sources

bioRxiv2023

Seed tuber imprinting shapes the next-generation potato microbiome

Potato seed tubers are colonized and inhabited by soil-borne microbes, some of which can positively or negatively impact the performance of the emerging daughter plant in the next season. In this study, we investigated the intergenerational inheritance of microbiota from seed tubers to next-season daughter plants by amplicon sequencing of bacterial and fungal microbiota associated with tubers and roots of two seed potato genotypes produced in six different fields. We observed that field of production and potato genotype significantly affected the seed tuber microbiome composition and that these differences persisted during winter storage of the seed tubers. When seed tubers from different production fields were planted in a single trial field, the microbiomes of daughter tubers and roots of the emerging plants could still be distinguished according to the field of origin of the seed tuber. Remarkably, we found little evidence of direct vertical inheritance of field-unique microbes from the seed tuber to the daughter tubers or roots. Hence, we hypothesize that this intergenerational "memory" is imprinted in the seed tuber, resulting in differential microbiome assembly strategies depending on the field of production of the seed tuber.

microbiology↗

bioRxiv2023

A tripartite bacterial-fungal-plant symbiosis in the mycorrhiza-shaped microbiome drives plant growth and mycorrhization

Plant microbiomes play crucial roles in nutrient cycling and plant growth, and are shaped by a complex interplay between plants, microbes, and the environment. The role of bacteria as mediators of the 400-million-year-old partnership between the majority of land plants and, arbuscular mycorrhizal (AM) fungi is still poorly understood. Here we test whether AM hyphae-associated bacteria influence the success of the AM symbiosis. Using partitioned microcosms containing field soil, we discovered that AM hyphae and roots selectively assemble their own microbiome from the surrounding soil. In two independent experiments, we identified several bacterial genera, including Devosia, that are consistently enriched on AM hyphae. Subsequently, we isolated 144 pure bacterial isolates from a mycorrhiza-rich sample of extraradical hyphae and isolated Devosia sp. ZB163 as root and hyphal colonizer. We show that this AM-associated bacterium synergistically acts with mycorrhiza on the plant root to strongly promote plant growth, nitrogen uptake, and mycorrhization. Our results highlight that AM fungi do not function in isolation and that the plant-mycorrhiza symbiont can recruit beneficial bacteria that support the symbiosis.

microbiology↗

bioRxiv2023

Congruent downy mildew-associated microbiomes reduce plant disease and function as transferable resistobiomes

Root-associated microbiota can protect plants against severe disease outbreaks. In the model-plant Arabidopsis thaliana, leaf infection with the obligate downy mildew pathogen Hyaloperonospora arabidopsidis (Hpa) results in a shift in the root exudation profile, therewith promoting the growth of a selective root microbiome that induces a systemic resistance against Hpa in the above-ground plant parts. Here we show that, additionally, a conserved subcommunity of the recruited soil microbiota becomes part of a pathogen-associated microbiome in the phyllosphere that is vertically transmitted with the spores of the pathogen to consecutively infected host plants. This subcommunity of Hpa-associated microbiota (HAM) limits pathogen infection and is therefore coined a "resistobiome". The HAM resistobiome consists of a small number of bacterial species and was first found in our routinely maintained laboratory cultures of independent Hpa strains. When co-inoculated with Hpa spores, the HAM rapidly dominates the phyllosphere of infected plants, negatively impacting Hpa spore formation. Remarkably, isogenic bacterial isolates of the abundantly-present HAM species were also found in strictly separated Hpa cultures across Europe, and even in early published genomes of this obligate biotroph. Our results highlight that pathogen-infected plants can recruit protective microbiota via their roots to the shoots where they become part of a pathogen-associated resistobiome that helps the plant to fight pathogen infection. Understanding the mechanisms by which pathogen-associated resistobiomes are formed will enable the development of microbiome-assisted crop varieties that rely less on chemical crop protection.

microbiology↗